A content-distribution network (CDN) may be a system of computers (e.g. edge servers) that cache or store copies of data at various locations. By placing copies of data at locations near end users, a CDN may improve access to the data by increasing access bandwidth and redundancy while reducing access latency. Data cached in a CDN may include, for example, text, graphics, media files (e.g. audio, photo, or video), scripts, Uniform Resources Locators (URLs), and database queries.
A social-networking system, such as a social-networking website, may enable its users to interact with it and with each other through it. The social-networking system may create and store a record (such as a user profile) associated with the user. The user profile may include demographic information on the user, communication-channel information for the user, and personal interests of the user. The social-networking system may also create and store a record of the user's relationships with other users in the social-networking system (e.g. a social graph), as well as provide social-networking services (e.g. wall-posts, photo-sharing, or instant-messaging) to facilitate social interaction between or among users in the social-networking system.